Supplemental air-brake mechanism.



A. DOAN. SUPPLEMENTAL AIR BRAKE MECHANISM.

APPLICATION FILED MAR. 10, 1909.

934:,293. Patented Sept. 14, 1909.

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WITNESSES. w I INVENTOR I ARTHUR DOAN ms ATTORNEY.

UNITED STATES ARTHUR DOA'N, OF OAKLAND, CALIFORNIA.

SUPPLEMENTAL AIRBRA*KE MEGI-IA'NISM.

Specification of Letters Patent.

Patented Sept. '14, 1909.

Application filed MarchilO, 1 909. 1S eriaITNo. 482,527.

To all whom {it mayxconcem:

Be it known that :1, AR'rHUn'DOAmcitizen of the United States, residing;at'OaklancLin the county of Alameda and ;State of :California, have invented new :and :useful I-mprovements in Supplemental Air-Brake Mechanism, of which the following is a specification.

This invention relates Lto air-brake systems for railway service, and pertains particularly to automatic safety appliances :for ;use in conjunction with systems already installed.

The objects ofmyinvention areto provide a device which will insure the proper and positive application of the wheelabrakes automatically under all conditions; ;to provide a safety apparatus that willautomatically chargeand discharge itself Without the directvattention of the engineer; to provide a device, in combination with the usual airbrake system, that will be effective to-apply su'tficient pressure to ;the :brake cylinder 'to cause the brakes'to stop rthe train in case=the train-line is broken, or pressure in the ,trainline becomes reduced so that theair pressure in the train line is unable to perform its required functions.

The invention .consists .of :the parts, ,and the construction and-combination of parts, as hereinafter more fully described and claimed, having reference to'the accompanying drawings, in =which- :Figure 31 is a diagrammatic elevation of the apparatus some parts being inisection. Fig. 2 {is a section of the three-way valve.

In the present embodimenoof my invention I employ an air-reservoir 2 which is connected to-the usual train-line or ,pipe 3 by pipe l, in which are imounted suitable check-valves 5 adapted to 'open to permit fluid to pass from the train-line 3 :into the reservoir 2, illlClstO prevent back flow to the train line when :the pressure -.in the latter is less than that in the reservoir 2; illhe pressureof fluid in the train-line?) is controlled by the @usual engineers valve 6 through which air is admitted from :i-he usual main reservoir ,7, this being charged by the pump 8. Thus when :the engineer opens the valve a6, allowing high pressure into'the train-line 3, the safety reservoir 2 is charged to an equal pressure with the trainzline. At .9 is shown the common triple valve through which air may be admitted into the -brake.,reservoir 10; whence it may again pass through =valve 9, (when the engineer operates :the control valve 6 .to reduce the pressure intrain line to the brake cylinder 1:1, and so operate the brakes in the usual :fashion.

iIt zhas "been found that sometimes, especiallywhentheatrain is running down along grade, the pressure in the brake reservoir 10 is allowed, through accident or carelessness, to :get so :lOW that it does not exert suflicient force on the brakes to check or hold the trains, thereby resulting in a runaway, or else calling for theapplicationlof the handbrakes. To obviate this, I connect thebrake cylinder 11, and the auxiliary reservoir 2 by a pipe 12, in which is disposed a three-way valve 13. Valve 13 is so arranged that :when it is :turned one way, the air may pass di rectly from the reservoir 10 to the brake cylinder .11, but when the valve is turned another ,way .(and which position is its normal position) :no air passes through pipe '12. Thepipes l;l2 constitute a buy-pass connection :between the train-line and brake cylinder 1'1 controlled by valve '13, and the latter is{controlledautomatically by the air pressure :in the train-line by the following means: Thevalve 13 is provided-with a handle 14,-:to-theefreeei1d of which a link 15'is connected to a piston-rod 116 secured in the piston ;17, slidable in thechamber 18. The upper end of chamber 18, above piston :17, communicates with the air pressure reservoir Qathrough the port 19 and pipe 20. Aspring 21 :acts on the under side of the piston to tend toiraiseit. The use of this spring however 518 optional. Port 19 is controlled by a needle-valve 22 secured in a piston 23 reciprocating in chamber 2 1, and the two chambers 18 and 24: are connected at their ends by the ports 19 and by a forked pipe 25 communicating with the train-line 3. The pressure of the air in the train line is normally-effective upon piston 23 to lift;the latter ,and :close valve 22, and also ,uphold piston 17 and close valve 13.

The operation is then as follows: Should of the pistons 17 and 23 below the normal high pressure in the supplemental tank 2, the piston 23 would be depressed by the spring 28 and allow the fluid in the reser' voir 2 to enter chamber 18 above the piston 17 and depress this, thus turning the lever 14 so that the valve 13 will be actuated, establishing direct communication betweenthe brake cylinder 11, and the high pressure reservoir 2. The pressure in the latter will then be effective to positively set the brakes irrespective of the pressure in the train-line 3. This gives the pump a chance to catch up in its work, and bring the air in the trainline again up to a safe pressure. As soon as normal pressure is again established through the system, the pistons 17 and 23 will be actuated through the pressure in pipe 25 to close valve 22, and turn the lever 14 to cut ofl" communication between the brake cylinder and the reservoir 2; the brakes then being taken care of by the air through reservoir 10. When the valve 22- closes the air above piston 17 escapes through port 26 in the piston casing and port 27 in the valve 22; which ports coincide only when the valve is seated so that there is no loss of pressure when the valve 17 is open.

Having thus described my invention, what I claim and desire to secure by Letters Patent is- 1. In an air-brake system, the combination with a train-line pipe and the brake cylinder, the auxiliary reservoir, triple valve, and connections between the train-line through the triple valve and auxiliary reservoir to the brake cylinder, of a bypass connection between the train-line and the brake cylinder around the triple valve, a valve in said by-pass, a high pressure reservoir chargeable from the train-line and interposed in said by-pass, and means control-led by the difference in pressure between said high pressure reservoir and the train-line for opening and closing the valve in the by pass.

2. The combination in an air-brake system, of a train-line, a brake cylinder, a high pressure reservoir connected with the train line and also having a fluid connection with the brake cylinder, a valve in said connection between the high pressure reservoir and the brake cylinder, and means operated by the difference in pressure between the high pressure reservoir and the train-line to actuate said valve, said last-named means including a cylinder inclosing a piston, which latter is connected with the stem of said valve, said valve being closed and opened by the movements of said piston, connections between the space at the top of said piston and said high pressure reservoir,

and a valve in said lastnamed connections and operable by the'pressure in the trainline.

3. The combination in an air-brake system, of a train-line, a brake cylinder, a high pressure reservoir connected with the trainline and also having a fluid connection with the brake cylinder, a valve in said connection between the high pressure reservoir and the brake cylinder, means operated by the diflerence in pressure between the high pressure reservoir and the train-line to actuate said valve, a piston operating in a cylinder, connections between the piston and said valve to operate the latter in unison with the movements of the piston, said'cylinder connected at one end with said high pressure reservoir and connected at the opposite end with the train-line independent of said high pressure reservoir, and a valve in said connections between said piston cylinder and high pressure reservoir, said valve operative through said connections between the piston cylinder and train-line.

4. The combination in an air-brake system, of a train-line, a brake cylinder, a high pressure reservoir connected with the trainline and also having a fluid connection with the brake cylinder, a valve in said connection between the high pressure reservoir and the brake cylinder, means operated by the diflerence in pressure between the high pressure reservoir and the train-line to actuate said valve, a piston operating in a cylin der and connected with the valve stem to operate the latter on the movement of the piston, said cylinder connected at one end with the high pressure reservoir and the other end connected with the train -line, and a valve in the said connections between said last-named cylinder and said high pressure reservoir, said valve having a stem connected with a piston operating in an independent cylinder, and which latter cylinder is also connected with the train-line independent of the high pressure cylinder.

5. The combination in an air-brake sys tem, of a train-line, a brake cylinder, a high pressure reservoir connected with the trainline and also having a fluid connection with the brake cylinder, a valve in said connection between the high pressure reservoir and the brake cylinder, means operated by the difference in pressure between the high pressure reservoir and the train-line to actuate said valve, a piston operating in a cylinder and connected with the valve stem to operate the latter on the movement of the piston, said cylinder connected at one end with the high pressure reservoir and the other end connected with the train-line, and a valve in the said connections between said lastnamed cylinder and said high pressure reservoir, said valve having a stem connected with a piston operating in an independent In testimony whereof I have hereunto set cyllnder, and which latter cyllnder 1s also my hand 1n presence of two subscribing wltconnected with the tram-line independent nesses.

of the high pressure cylinder, the stem of ARTHUR DOAN. said last-named valve having a port regis- Vitnesses: trable with exhaust ports in said first-named CHARLES A. PENFIELD,

piston cylinder. CHARLES EDELMAN. 

